Upon his adoption, Octavius assumed his great-uncle's name Gaius Julius Caesar.Roman citizens adopted into a new family usually retained their old nomen in cognomen form (e.g., Octavianus for one who had been an Octavius, Aemilianus for one who had been an Aemilius, etc.).Mark Antony was amassing political support, but Octavian still had opportunity to rival him as the leading member of the faction supporting Caesar.Mark Antony had lost the support of many Romans and supporters of Caesar when he initially opposed the motion to elevate Caesar to divine status.He rejected monarchical titles, and instead called himself Princeps Civitatis ("First Citizen of the State").The resulting constitutional framework became known as the Principate, the first phase of the Roman Empire.
Because of this, Octavius was raised by his grandmother, Julia, the sister of Julius Caesar.
His paternal great-grandfather Gaius Octavius was a military tribune in Sicily during the Second Punic War.
His grandfather had served in several local political offices.
Augustus dramatically enlarged the Empire, annexing Egypt, Dalmatia, Pannonia, Noricum, and Raetia; expanding possessions in Africa; expanding into Germania; and completing the conquest of Hispania.
Beyond the frontiers, he secured the Empire with a buffer region of client states and made peace with the Parthian Empire through diplomacy.
Octavian found consul Mark Antony, Caesar's former colleague, in an uneasy truce with the dictator's assassins.